Recently, from a standpoint of security, a technology for monitoring a mobile object such as an automobile that travels on a road is proposed. Further, the technology is a technology for determining and detecting whether a mobile object that travels on a road is any one of an automobile (four-wheel vehicle), a bike (two-wheel vehicle), a bicycle (two-wheel vehicle), and a pedestrian.
In particular, from a standpoint of safety and illegality, whether a person who rides on the two-wheel vehicle wears a helmet is expected to be detected.
To cope with the above, a technology for detecting whether the person who rides on the two-wheel vehicle wears the helmet is proposed (for example, see Patent Literature 1).
In the invention of Patent Literature 1, an image processing unit processes an image produced from a camera and detects an imaged person. When the person is detected, the image processing unit determines whether the person wears the helmet. In a determination method, a face and a head of a person are first detected and on the basis of a ratio between a width of the face and a width of the head, it is determined whether the helmet is worn.